This page summarizes some of the similarities and differences between Arch and other distributions. This question comes up repeatedly and it would be nice to have a standard response. Please note: the best way to compare Arch to other distributions is to install it and try it yourself. Arch has a wonderful user community that is always willing to help new users. The summaries below are meant only to give you enough information to decide if Arch is really for you.

Arch vs Crux

Arch Linux is descended from Crux. Judd once summarized the differences:

"I used Crux before starting Arch. Arch started out as Crux, pretty much. Then I wrote pacman and makepkg to replace my bash pseudo packaging scripts (I built Arch as an LFS system to begin). So the two are completely separate distros, but technically, they're almost the same. We have dependency support (officially) for example, although Crux has a community that provides other features. CLC's prt-get will do rudimentary dependency logic. Crux gets to ignore lots of problems we have too, since it's a very minimalistic package set, basically what Per uses and nothing else."

Arch vs Sorcerer/Lunar-linux/Sourcemage

Sorcerer/Lunar-linux/Sourcemage (SLS) are all source based distros, much like Gentoo is, but are originally related to one another. SLS distro's use a rather simple set of script files to create packages descriptions, and use a global configuration file to configure the compilation process, much like Arch's ABS system. The SLS tools do full dependancy checking (including handling optional features) and package tracking (and deinstalling/upgrading). There are no binary packages for any of the SLS family, although they all can rollback earlier installed packages easily.

The install involves installing a base system (much like Arch's: i686 optimized, CLI and ncurses menus, only core tools), then recompiling the base system (optionally) afterwards. There is obviously no "standard" WM/DE/DM and they do not install an Xserver during the base installation. But they do provide you with an easy way of installing one of several Xserver alternatives (xorg 6.8 or 7, xfree86).

Arch vs Rock

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Arch vs T2

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Arch vs Graphical Distros

The graphical distros have a lot of similarities, and Arch is very different from any of them. Arch is text based and command-line oriented. Arch is a better distro if you want to truly learn Linux. Graphical-based distros tend to ship with GUI installers (like Fedora's Anaconda) and GUI system configuration tools (like SuSE's Yast). Specific differences between distros are described below.
albert frikie

Arch vs Slackware

Slackware and Arch are both 'simple' distributions. Both use BSD-style init scripts. Arch supplies a much more robust package management system in pacman which, unlike Slackware's standard tools, allows simple automatic system upgrades. Slackware is seen as more conservative in its release cycle, preferring proven stable packages. Arch is much more 'bleeding edge' in this respect. Arch is i686 only whereas Slackware can run on i486 systems. Arch is a very good system for Slack users who want more robust package management or more current packages.

Arch vs Debian

Arch is simpler than Debian. Arch has fewer packages. Arch provides better support for building your own packages than Debian does. Arch is more lenient when it comes to 'non-free' packages as defined by GNU. Arch is i686 optimized and thus faster than Debian (NO documented proof here either). Arch packages are more bleeding edge than Debian packages (Arch current is often more up-to-date than Debian testing!)

Arch vs Ubuntu

Arch has a simpler foundation than Ubuntu. If you like to compile your own kernels, try out bleeding edge CVS-only projects, or build a program from source every once in a while, Arch is better suited. If you want to get up and running quickly and not fiddle around with the guts of the system, Ubuntu is better suited. In general, developers and tinkerers will probably like Arch better than Ubuntu.

Arch vs RPM-based Distros

RPM packages are available from many, many places, but third-party packages often have dependency issues such as requiring an old version of a library. There is also confusion between RPM packages for Red Hat and RPM packages for Mandrake. (These are issues I had as a Linux newbie with Mandrake 8.2, and may not reflect the current situation.) pacman is much more powerful and reliable than RPM.

Arch vs Fedora

Fedora is a spin-off from the Red Hat distribution and has continually been one of the most popular distributions to date. Therefore, there is a massive community and lots of pre-built packages and support available. Like all RPM-based distributions, package management is a problem. Fedora supplied Yum as a front-end to manage the acquistion of RPMs and dependency resolution. The system lacks solid yum integration. Fedora does innovate and recently earned kudos for integration of SELinux and GCJ compiled packages to remove the need for Sun's JRE. Fedora famously doesn't attempt to support the mp3 media format due to perceived patent issues.

Arch vs Mandriva

Mandriva (previously Mandrake), though famed for its installer, is a very handholding distro which can get annoying after some time. Another problem is that it is an RPM-based distro as discussed above. Arch allows much more freedom and less hand-holding. You actually learn to use Linux.

Arch vs SUSE

SUSE is centered around its well-regarded Yast configuration tool which is a one-stop shop for most users' configuration needs. Arch doesn't offer such a facility as it goes against TheArchWay. SUSE, therefore, is seen as more appropriate to less-experienced users, or those who want a simpler life with expected functionality working out of the box. SUSE doesn't offer mp3 support immediately after installation, but that can easily be added later through Yast.

Arch vs Frugalware

Arch is text based and command-line oriented (user should be willing to learn).
Frugalware is a Slackware-based system. Frugalware provides better multi-lingual support. Frugalware also provides more local documentation. Frugalware claims to be faster than Arch.
Both use pacman. Their packages are not really very compatible.